Measuring feet, lasts and footwear

SATRA devices which help to provide a good fit and satisfied customers.

by Peter Allen

Good fit is a key factor in a customer’s choice of footwear at the point of sale. A poor customer experience at the initial fitting can lead to a lost sale. If the sale is made but, with subsequent wear, discomfort or rubbing occurs, the customer could turn to another brand or retailer at next time of purchase.

Important factors contributing to the fit of footwear are the user’s foot size, the size and shape of the last from which the footwear was produced and the size and shape of the finished product. The footwear’s final shape is governed not only by the last shape, but also by the footwear detail design and manufacturing processes employed. These include the characteristics of the upper materials and components, pattern design and shoemaking processes (such as lasting and heat setting).

SATRA has a long track record in establishing the requirements of footwear sizes, last dimensions and fit requirements. In support of obtaining good fit, SATRA also produces a number of products which can be used to measure feet, footwear or lasts. This article outlines some of these measuring devices and equipment produced by SATRA.

Foot measurement at the point of retail sale

Where a retailer interfaces directly with customers to establish their correct size of shoe, the SATRA STD 224 fitting board is useful and simple to use, and gives appropriate length and five width fittings. The standard board is designed to be used with weight applied on the foot, and so captures the foot spread under load. There are three fitting boards available for men, women and children. For members requiring a large number of fitting boards (typically 50 or more), it is possible to customise the standard board to incorporate specific size ranges, width fittings, colours, customer logos or messages. A design service is also available for the layout of these larger bespoke orders.

The SATRA STD 219 size stick is a simple device used to determine foot length. It is applicable for measuring both left and right feet, and is designed to give an accurate length with load on the foot. The standard stick is marked with UK shoe sizes and millimetres. However, bulk quantities can be produced with different sizes indicated. In conjunction with a size stick and with experience, additional width information can be obtained using a tape – such as the measurement of the joint girth.

Whole shoe measurements

The SATRA STD 206 quarter and back height gauge and the SATRA STD 225 internal shoe size gauge allow measurements to be made of some key characteristics of completed footwear. The height of the topline of a shoe at the back and at the quarters affects both fit and comfort. If the back height is too low, heel slip may occur during walking.

On the other hand, if the topline (particularly of the outer quarters) is too high, rubbing can result. STD 206 is an instrument designed to measure the height of the topline of the shoe above the insole surface at the seat, to check that the heights mentioned above fall within guidelines. The gauge can be used for a wide range of shoe sizes and incorporates an adjustment which allows the measuring position for quarter height to be varied correctly with shoe size. The instrument is supplied with full instructions and tables giving measurement positions for adults’ footwear, as well as for children’s shoes.

The SATRA STD 225 internal shoe size gauge is an easy-to-use device used to estimate the approximate size of footwear, based on measuring the internal length of footwear. The gauge comprises a flat bar, which is inserted in the shoe and pushed into the toe. A movable heel section slides over a measuring scale, thus allowing a curved heel bar to be positioned in contact with the inside of the heel. The length is then determined by moving the device vertically and locating the curved bar to the point of maximum heel curvature. At this point, the size of the footwear can be read off the scale. There are four standard versions of the internal shoe size gauge available, which cover the adults’ sizes – two marked in UK sizes and two marked in millimetres. Again, bulk quantities can be supplied with different sizes.

Measuring lasts

The dimensions and shape of the last – or a sole moulding foot – are crucial to the final shape of the completed footwear and, hence, its fit. A poorly shaped or badly proportioned last will impart poor fitting characteristics to the footwear.

To aid the process of ensuring lasts are correctly shaped and dimensioned, SATRA produces a digital last assessment jig (SATRA STD 223). The jig allows a last to be set at an appropriate orientation with the heel raised as in the shoe. Several key dimensions can then be checked. The jig allows accurate repeatable dimensions to be taken on both left and right foot lasts. There are two built-in digital slides which can be zeroed at the appropriate datum position, and from which dimensions are taken. The jig also includes an angled measurement device that facilitates the location of the last joint line. A separate pair of digital callipers and a toe spring gauge are also supplied. SATRA members can purchase associated SATRA test methods, which relate to the last measuring process.

A periodic review of last dimensions is recommended to check for any drift in standards. Many last designs are based on historical and empirical data, and new lasts are often produced by modifying previously used lasts. Over time, there is a risk that last dimensions can drift away from the ideal, resulting in degraded fitting characteristics.

SATRA last assessments

In addition to the supply of the test devices and equipment described in this article, SATRA can also conduct last assessments for members. For example, a last assessment was conducted on a number of lasts for a member, resulting in recommendations for modifications to these lasts. New lasts were produced, and very positive feedback was received regarding the improved fit following production of footwear using these new lasts.

Click here for comprehensive information on SATRA's range of test equipment.

Publishing Data

This article was originally published on page 30 of the June 2012 issue of SATRA Bulletin.

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